Waveguide circulators are known in the art for handling RF waves. Typically, waveguide circulators include three ports (although more or less ports are possible) and are used for transferring wave energy in a non-reciprocal manner, such that when wave energy is fed into one port, it is transferred to the next port only. A common use for waveguide circulators is to transmit energy from a transmitter to an antenna during transmitting operations, and to transmit energy from an antenna to a receiver during receiving operations.
In order to enable the non-reciprocal energy transfer, the waveguide circulators include ferrite resonators to which are applied a magnetic field via one or more magnets or electromagnets. In order to match the impedance of the ferrite gyrator (which includes the ferrite resonators and their mounting posts) to the input waveguides, a matching network is inserted between them. However, in practice, a conventional circulator with a ferrite gyrator coupled to a ¼ wavelength transformer produces a frequency response of about 21 dB return loss over a 26% frequency bandwidth. This is not the desired handling of the circulator.
In light of the above, there is a need in the industry for an improved waveguide circulator that alleviates, at least in part, the deficiencies with existing waveguide circulators.